1. Field of the Invention
The present invention relates to the field of shoe sole design and construction. More particularly the present invention relates to the field of design and construction of the midsole and outsole of athletic shoes.
2. Description of the Prior Art
Shoe sole design and construction is an old art. Over the years numerous different types of shoe soles have been introduced and developed. The following prior art references are found to be relevant to the art.
1. U.S. Design Pat. No. Des. 266,371 issued to Stubblefield on Oct. 5, 1982 for "Shoe Sole" (hereafter "the '371 Design Patent").
2. U.S. Design Pat. No. Des. 267,366 issued to Davis on Dec. 28, 1982 for "Shoe Sole" (hereafter "the '366 Design Patent").
3. U.S. Design Pat. No. Des. 269,139 issued to Stubblefield on May 31, 1983 for "Athletic Shoe Outer Sole" (hereafter "the '139 Design Patent").
4. U.S. Design Pat. No. Des. 282,123 issued to Davis on Jan. 14, 1986 for "Shoe Outsole" (hereafter "the '123 Design Patent").
5. U.S. Pat. No. 1,111,437 issued to Butterfield on Sep. 22, 1914 for "Composite Boot And Shoe" (hereafter "the '437 Patent").
6. U.S. Pat. No. 1,364,570 issued to Martin on Jan. 4, 1921 for "Shoe Sole" (hereafter "the '570 Patent").
7. U.S. Pat. No. 1,736,576 issued to Cable on Nov. 19, 1929 for "Elastic Shoe Sole" (hereafter "the '576 Patent").
8. U.S. Pat. No. 1,962,526 issued to Riddell on Jun. 12, 1934 for "Basket Ball Shoe" (hereafter "the '526 Patent").
9. U.S. Pat. No. 2,134,598 issued to Burns on Oct. 25, 1938 for "Metatarsal Nonslip Sole" (hereafter "the '598 Patent").
10. U.S. Pat. No. 2,424,463 issued to Hogg on Jul. 22, 1947 for "Multiple Antiskid Ribbed Suction Sole For Shoes And Rubber Footwear" (hereafter "the '463 Patent").
11. U.S. Pat. No. 2,887,794 issued to Masera on May 26, 1959 for "Shoe Made of Thermo-Plastic Or Thermo-Setting Material Or the Like" (hereafter "the '794 Patent").
12. U.S. Pat. No. 3,100,354 issued to Lombard et al. on Aug. 13, 1963 for "Resilient Shoe Sole" (hereafter "the '354 Patent").
13. U.S. Pat. No. 4,096,649 issued to Saurwein on Jun. 27, 1978 for "Athletic Shoe Sole" (hereafter "the '649 Patent").
14. U.S. Pat. No. 4,259,792 issued to Halberstadt on Apr. 7, 1981 for "Article of Outer Footwear" (hereafter "the '792 Patent").
15. U.S. Pat. No. 4,335,530 issued to Stubblefield on Jun. 22, 1982 for "Shoe Sole Construction" (hereafter "the '530 Patent").
16. U.S. Pat. No. 4,372,058 issued to Stubblefield on Feb. 8, 1983 for "Shoe Sole Construction" (hereafter "the '058 Patent").
17. U.S. Pat. No. 4,449,307 issued to Stubblefield on May 22, 1984 for "Basketball Shoe Sole" (hereafter "the '307 Patent").
18. U.S. Pat. No. 4,481,727 issued to Stubblefield on Nov. 13, 1984 for "Shoe Sole Construction" (hereafter "the '727 Patent").
19. U.S. Pat. No. 4,494,320 issued to Davis on Jan. 22, 1985 for "Shoe Outsole" (hereafter "the '320 Patent").
20. U.S. Pat. No. 4,494,321 issued to Lawlor on Jan. 22, 1985 for Shock Resistant Shoe Sole" (hereafter "the '321 Patent").
21. U.S. Pat. No. 4,546,556 issued to Stubblefield on Oct. 15, 1985 for "Basketball Shoe Sole" (hereafter "the '556 Patent").
22. U.S. Pat. No. 4,550,510 issued to Stubblefield on Nov. 5, 1985 for "Basketball Shoe Sole" (hereafter "the '510 Patent").
23. U.S. Pat. No. 4,562,651 issued to Frederick et al. on Jan. 7, 1986 for "Sole with V-Oriented Flex Grooves" (hereafter "the '651 Patent").
24. U.S. Pat. No. 4,577,422 issued to Tanel on Mar. 25, 1986 for "Athletic Shoe With Improved Pivot Cleating" (hereafter "the '422 Patent").
25. U.S. Pat. No. 4,697,361 issued to Ganter et al. on Oct. 6, 1987 for "Base For An Article of Footwear" (hereafter "the '361 Patent").
26. U.S. Pat. No. 4,741,114 issued to Stubblefield on May 3, 1988 for "Shoe Sole Construction (hereafter "the '114 Patent").
27. International Publication published under Patent Corporation Treaty (PCT) No. WO 89/05105 (hereafter "the PCT Publication '105").
28. French Patent No. 2,500,278 (hereafter "the French Patent").
The '371 Design Patent (1982) discloses a shoe outsole design having a plurality of downwardly and outwardly inclined lugs or levers.
The '366 Design Patent (1982) discloses a shoe outsole design having the general appearance of a figure eight (8).
The '139Design Patent (1983) discloses a shoe outsole design having an outmost row of downwardly and outwardly inclined lugs and several inwardly spaced additional rows of lugs of lesser vertical dimensions.
The '123 Design Patent (1986) discloses a shoe outsole design having the general appearance of a figure eight (8), which is similar to the one shown in the '366 Design Patent (the portion of the term of the '123 Design Patent subsequent to the expiration date of the '366 Patent has been disclaimed). There is a crosshatched pattern of grooves cut into the bottom surface of the outsole of the '123 Design Patent.
The '437 Patent (1914) discloses a composite boot or shoe outsole 14 having a tread bottom surface. The ball portion and the heel portion of the tread bottom surface has elongated diamond forms d, and the marginal portion of the tread bottom surface is notched or scored with short, parallel transverse channels c.
The '570 Patent (1921) discloses a shoe sole 1 having a raised portion 5 at the ball portion of its bottom surface. The raised portion 5 is made concave to form a recess 6. A raised extension 8 is formed upon the raised portion 5 and extends rearwardly to the instep portion 3 terminating in an abrupt shoulder 9 which is adapted to contact with an ordinary shoe heel.
The '576 Patent (1929) discloses an elastic shoe sole having a top side and a bottom side. The ball portion of the top side is bowed into a convex form 11, and the ball portion of the bottom side is recessed into a concave form 13 surrounded by a circular boss 12. The ball portion of the bottom side further has two longitudinal ribs 16 surrounding the circular boss 12. The toe portion of the bottom side has a transversely elongated and forwardly thinned boss 14 and a plurality of transverse ribs 15.
The '526 Patent (1934) discloses a basketball shoe having a sole and an upper 2 independently sewn onto an intermediately disposed welt 3. The bottom surface of the sole 1 is dished at 14 to form a marginal bearing ridge 15, where the dishing is deepest at its heel portion 16, shank portion 17 and toe portion 18.
The '598 Patent (1938) discloses a metatarsal nonslip shoe sole 1 having a longitudinally extended substantially oval shaped concavity or depression 5 at its bottom surface.
The '463 Patent (1947) discloses a shoe or rubber footwear sole 5 having a plurality of small round molded suction cups such as suction cups 9, 14, 19 and 20, and skid resisting areas surrounding each suction cup. Each skid resisting area is formed with a group of molded skid resisting ribs, such as intersecting groups 11 and 12 at area 10 surrounding suction cup 9, and groups 15, 16 and 17 at areas surrounding suction cups 14, 19 and 20 respectively.
The '794 Patent (1959) discloses a thermoplastic or thermo-setting high-heel shoe sole A having a central depression 1 at the ball portion of its bottom surface. The central depression 1 is provided with a central projection 7 and cross-ribs 8, and surrounded by a pair of parallel border ribs 2. A resilient member 6' may be inserted into the continuous channel 3 formed between the two parallel border ribs 2.
The '354 Patent (1963) discloses a resilient shoe sole 11 having two oppositely disposed longitudinal outer rims 12 and 13 at its bottom. Defined by the two longitudinal outer rims 12 and 13 there is a longitudinal groove extending through the entire length of the ball and instep portions of the sole 11.
The '649 Patent (1978) discloses an athletic shoe sole 10 having a multiplicity of downwardly extending flanges including an outer peripheral flange 22, a heel section flange 24, a toe section flange 26 and a reinforcing transverse flange 30. The multiplicity of flanges define a multiplicity of recesses which are upwardly concave, including a toe section recess defined by the toe section flange 24 which is upwardly concave in both the longitudinal and lateral directions of the sole 10.
The '792 Patent (1981) discloses a running shoe 10 having a shoe base 12 and a shoe upper 14. The shoe base 12 has a multi-layer heel part integral with a sole part. The bottommost layer 22 of the heel part has two oppositely disposed and outwardly projected longitudinal fins 28 and 30 forming a longitudinal recess at the bottom of the heel part.
The '530 Patent (1982) discloses a shoe sole 12 having a midsole 16 and an outsole 18. The outsole 18 has a large opening 26 at its ball portion and a small opening 28 at its heel portion for allowing a front protruding portion 30 and rear protruding portion 32 of the midsole 16 to extend through respectively. The lower surface of the front protruding portion 30 of the midsole 16 has a longitudinal concavity 34 as well as a transverse concavity 36.
The '058 Patent (1983) discloses an athletic shoe outsole 6 having at its bottom surface an outmost row of downwardly and outwardly inclined lugs 7, and two inwardly spaced additional rows of lugs 22 and 23 of lesser vertical dimensions which are similar to the ones shown in the '139 Design Patent. The rows of lugs define a longitudinal and transverse concavity at the bottom surface of the outsole 6.
The '307 Patent (1984) discloses a basketball shoe outsole 10 having an inner surface 17 and an outer surface 13. In the central portion of the inner surface 17 there is a pedestal structure 100. In the rear foot portion 25 of the bottom surface 13 there are two outer rows of downwardly and outwardly inclined levers 14-40 adjacent respectively to the two opposite side edges of the bottom surface 13.
The '727 Patent (1984) discloses a shoe sole 12 which is similar to the one disclosed in the '530 Patent (the application of the '727 Patent is a division of the application of the '530 Patent). The shoe sole 12 has a midsole 16 and an outsole 18. At the bottom surface of the outsole 18 there are a plurality of downwardly and outwardly inclined lugs or levers 20 which are similar to the ones shown in the '371 Design Patent.
The '320 Patent (1985) discloses a shoe outsole 10 having the general appearance of a figure eight (8) with a crosshatched pattern of grooves 40 cut into the bottom surface 19 of the outsole 10, which is similar to the one shown in the '123 Design Patent. The bottom surface 19 of the outsole 10 has two generally oval shaped depressed regions 21 and 25 formed in the heel and toe regions 14 and 16 respectively.
The '321 Patent (1985) discloses a shock resistant shoe sole 12 having three inverted cup shaped cavities 20, 22 and 24 respectively located under the three natural contact points 60, 62 and 64 of a human foot 54. Cavity 20 is located directly under heel bone 60, cavity 22 is located directly under the first metatarsal 62, and cavity 24 is located directly under the fifth metatarsal 64.
The '556 Patent (1985) discloses a basketball shoe outsole 10 which is similar to the one disclosed in the '307 patent (the application of the '556 Patent is a continuation of the application of the '307 Patent, and the portion of the term of the '556 Patent subsequent to the expiration date of the '307 Patent has been disclaimed).
The '510 Patent (1985) discloses a basketball shoe outsole 10 which is similar to the one disclosed in the '307 Patent (the application of the '510 Patent is a division of the application of the '307 Patent). The outsole 10 has an inner surface 17 and an outer surface 13. In the forefoot portion of the outer surface 13 there is formed an oval herringbone tread surface 62 which has a plurality of grooves 64 and ridges 66. In the area under the head of the ball of the big toe of a wearer's foot there is a pivot stud 70 in the form of a concave cup and surrounded by concentric semi-circular grooves 68 which are an extension of grooves 64.
The '651 Patent (1986) discloses a shoe sole 14 having a midsole layer 18 and an outsole layer 20. At the bottom surface of the outsole layer 20 there are a plurality of cleats 24 and two straight grooves 30 an 32. The first groove 30 is aligned and coextensive with a first line extending substantially parallel to a medial metatarsal-phalanges line which extends between the first and second metatarsal-phalanges joints. The second groove 32 is aligned and coextensive with a second line extending substantially parallel to a lateral metatarsal-phalanges line which extends along the second through fifth metatarsal-phalanges joints. The first and the second grooves 30 and 32 join one another at the medial edge of the sole 14 to form a V-shaped configuration.
The '422 Patent (1986) discloses a shoe sole 14 for athletic field sports shoes. The sole 14 has a circular cleat 26 and a concentric standard tapered cleat 38 at the ball portion 22 and toe portion 24 of the sole 14, and a plurality of standard tapered cleats 36 at the heel portion 18 of the sole 14.
The '361 Patent (1987) discloses a shoe sole 1 having a multiplicity of recesses with different depths at its lower surface 2. The multiplicity of recesses includes a deep recess 6 below the big toe 13 of a foot 8, a shallow recess 7 below one or more of the small toes 14, a transverse recess 5 located below the ball portion 12 of the foot 8, an elongated recess 4 located at the instep portion 18, and a deep recess 3 below the heel 9 of the foot 8.
The '114 Patent (1988) discloses an athletic shoe sale 2 which is similar to the one disclosed in the '058 Patent. The athletic sole has a modified midsole 36 and an outsole 25. The transverse cross-section of the heel portion of the midsole 36 has a generally trapezoidal configuration, where the lower surface 39 of the midsole 36 has a transverse concavity. With rows 38, 40 and 41 of the downwardly and outwardly inclined lugs at the bottom surface of the outsole 25, the combination supports the athletic shoe construction in a cantilevered fashion.
The PCT Publication '105 (1989) discloses a shoe sole 1 having a midsole and an outsole. The outsole has an opening at its heel portion for allowing a projection 2 to extend downwardly through the opening.
The French Patent (1982) discloses a shoe sole having an upper surface and a lower surface. The lower surface of the sole has a large concavity 12 at its ball portion 11 and a small concavity 8 at its heel portion 7.
There are some well established general requirements for shoe sole design and construction. The shoe sole must: (a) provide overall comfort to the wearer's foot; (b) maintain adequate cushioning to the wearer's foot bones; (c) provide adequate protection from slippage; (d) have durable wearing life; (e) be easy to manufacture; and (f) be inexpensive to manufacture. As demonstrated by the prior art references, an effective way to fulfill these requirements is to modify the configuration and structure of a shoe sole.
Today a typical athletic shoe sole includes an insole, a midsole and an outsole. The insole contacts a wearer's foot, the outsole contacts the ground, and the midsole is sandwiched in between. Usually the insole is made of soft materials, the midsole is made of resilient material, and the outsole is made of hard materials.
As shown in FIG. 1, a human foot 10 can be divided into four major portions: a toe portion 12, a ball portion 14, an instep portion 16 and a heel portion 18. Accordingly, the insole, midsole and outsole portions each have four major portions: the toe portion, the ball portion, the instep portion and the heel portion, each respectively located below the corresponding portions of the human foot. The forces exerted on the human foot are most concentrated at its ball portion and heel portion.
In order to provide overall comfort and adequate cushioning to a wearer's foot, many prior art references have focused on the modification of the bottom surface of the outsole. One approach is to have some recesses or concavities at several locations, most commonly the ball portion and the heel portion. This approach can be found in many prior art references such as the '463 Patent, the '649 Patent, the '320 Patent, the '321 Patent, the '361 Patent and the French Patent. Another approach is to have some patterned projections or convexities at the bottom surface of the outsole. This approach can also be found in many prior art references such as the '058 Patent, the '307 Patent, the '727 Patent and the '422 Patent.
In addition to the general requirements, there are several more critical requirements for athletic shoe sole design and construction. These more critical requirements include: (a) high impact absorbability; (b) superb stability; and (c) maximum flexibility. These extra requirements are particularly important for basketball shoe soles. This is primarily due to the fact that basketball players' feet experience tremendous impact during running, jumping and landing which is much greater than the impact of normal standing, walking or jogging. Additionally, basketball players' feet are more likely to suffer ankle twists and similar injuries and basketball players' feet substantially elongate in the jumping position.
Several prior art references are directly related to basketball shoe soles. One way to improve impact absorption and avoid ankle injuries is to construct the outsole of a basketball shoe with so-called "cantilevered construction", which is disclosed in prior art references such as the '307 Patent, the '556 Patent and the '510 Patent. The cantilevered construction has two oppositely disposed rows of downwardly and outwardly inclined lugs constructed as part of the outsole to provide more cushioning to a wearer's foot. The cantilevered construction is further designed to provide more support along the inboard and outboard edges of the outsole, so the wearer's foot is properly centered. However, the cantilevered construction of these basketball shoe outsoles is mainly located in the rear foot area of the wearer's foot, whereas in the jumping position, a basketball player's foot is bent such that most of the force is exerted on the forefoot area. Additionally, when the basketball player lands on his forefoot, he is very likely to land off the center and injure his ankle. Therefore it is desirable to substantially improve the cushioning and ankle twist protection to the forefoot area.
There is an important factor which has not been recognized by any prior art references discussed above. This important factor is that a basketball player's foot elongates substantially in the bending position. Referring to FIG. 1, in the normal standing position or full stepping position, the total length of the human foot 10 is the sum of two segments AB and BD, where BD is the straight distance BC'D between points B and D. However, in the jumping up or landing down position, the human foot 10 is bent as shown in FIG. 2. In the maximum bending position shown in FIG. 2, the total length of the human foot 10 is the sum of three segment AB, BC and CD. Since the instep portion 16 of the human foot 10 is now fully stretched, the actual length BCD from point B to point D is longer than the direct straight distance BC'D between points B and D shown in FIG. 1. This factor is more clearly illustrated in FIG. 3, where the length of the arched shaped curve BCD is definitely longer than the length of the straight line BC'D. It is clear that the basketball player's foot actually elongates when it is bent for jumping up or landing down on his forefoot. Unfortunately, the prior art basketball shoe soles will not elongate with the basketball player's foot. In addition, most of the prior art basketball shoe soles include a midsole which generally has equal thickness at its ball portion. This prevents a shoe sole from following the bending of the ball portion of a foot. These disadvantages intensify the fatigue of basketball players' feet.